Hunger is one of our primal human urges, but it’s a tough thing to grasp, a marionette with many masters. A variety of hormones and neurotransmitters pull the strings – appetite suppressors and boosters, plus others that affect satiety and stress – and they, in turn, are manipulated by your body clock. There are two kinds of hunger: physiological and reward-driven. One is ruled by your body’s instinct to find the energy it needs to survive, while the other is psychological, influenced by smell, sight, stress and social and environmental settings – the gauntlet of daily life. And then you find yourself loading up with a fistful of biscuits at midnight. The problem is, your body often struggles to differentiate between the two: do you really need fuel, or did you just watch an ad for a flame-grilled bacon and cheese burger? New research is revealing ways you can control your brain’s reward system to shrink your waistline. For instance, Dr Heather Leidy, an assistant professor of nutrition and exercise physiology at the University of Missouri, used functional MRI technology to find out how people’s reward centres responded to appetising images of food after they’d eaten or skipped breakfast. She found that eating a protein-rich breakfast can dampen hunger all day. Use this strategy – and the rest that follow – to gain the upper hand on your appetite. Just remember that hunger is like a beast: you can’t stop it, but you can contain it.

Physiological hunger arises from an imbalance in your kilojoules-in/kilojoules-out equation. To deal with hunger rationally, you have to tally your kilojoules consumption and compare the result with your total kilojoule burn. This helps you identify and ignore reward-driven cues. WINNING STRATEGY: Use a kilojoule-target calculator to estimate the kilojoules you need to maintain your weight. You can search for one of these calculators online and simply input your stats. Write down everything you eat and drink for a couple of days. If you’re near that kilojoule number and your weight is staying steady, then most of your hunger pangs are reward-driven. To lose weight, cut your intake by up to 2 000kJ a day.

Studies using a simple salad have changed the way nutritionists think about hunger. Dr Barbara Rolls, a professor of nutritional sciences at Penn State University, examined the impact of eating a large-volume, 418kJ salad – 3 cups of chopped lettuce, ½ medium carrot, 1 sliced radish, ½ tomato, 2 tablespoons of reduced-fat grated cheddar cheese and ½ medium cucumber tossed with 2 tablespoons of reduced-fat dressing – before or with dinner. People who ate the salad, regardless of timing, reported greater satiety and ate 11% less in total kilojoules. Another study by Rolls found that consuming a broth-based soup or an apple before a meal can help curb kilojoule intake. The reason is that we tend to eat a fixed weight of food each day, regardless of kilojoule or nutrient content. WINNING STRATEGY: Eat as much as you can of foods with very low kilojoule densities – such as non-starchy vegetables, broth-based soups and fruit, says Rolls. Consume reasonable amounts of low-density stuff, like wholegrains, legumes, lean protein, starchy vegetables and low-fat dairy. Eat only small portions of medium-density foods, like bread, cheese, nuts, and higher-fat meat and dairy. And obviously, limit those high-kiloujoule-density food bombs, like fried snacks, sweets and biscuits.

When you’re stressed, your body releases the hormone cortisol, which can interfere with insulin and boost your blood glucose – instant fuel for outsprinting a predator on the savannah. But unless you’re actually running away from your supervisor, that fuel tends to become belly fat, even as stress strengthens hunger. Worse, stress can make you eat more fatty, salty and sugary foods, a recent study in the journal Appetite found. WINNING STRATEGY: For some quick fixes, see our quiz on this page. For longer-term solutions, “dissipate stress and you’ll dissipate stress eating,” says psychologist Dr Lisa Groesz, author of the study in Appetite. “Think about how you interpret stressful events. Then let go of what is not in your control,” she says. And try to exercise every day; exercise is a proven stress reducer, but not because of the flood of endorphins, says Dr Robert Thayer, a professor of psychology at California State University. More likely it’s through the interaction of norepinephrine and serotonin, which are neurotransmitters that help your brain deal with stress.

Leidy’s research suggests that consuming high-protein meals can reduce reward-driven hunger. “Our study looked at the impact of protein at breakfast, but I would suspect that eating a high-protein snack in the afternoon would also reduce reward-driven hunger later in the evening.” Leidy also determined that a satiety hormone known as peptide YY, or PYY, remained elevated for several hours after a high-protein meal. WINNING STRATEGY: Eat 20 to 30 grams of protein at every meal and always for your afternoon snack. A cup of plain yoghurt with 1 tablespoon of chia seeds and a ¼ cup of raspberries works well: protein in the yoghurt, and fibre from the seeds and fruit, will slow the release of food from your stomach while also stimulating PYY.

When you lose weight rapidly, your hunger hormones don’t adjust to your curtailed food intake. You crave the kilojoule amounts of your fatter former self. That’s one reason why extreme diets can cause weight fluctuations. To avoid that fate, shift your personal energy-balance equation delicately: reduce your intake by no more than 2 000kJ a day and burn more kilojoules by exercising more often and more intensely, says Brad Schoenfeld, author of The Max Muscle Plan (R223, kalahari.com). And when you add activity, you can eat a little more, which helps normalise your hunger hormones. A 2010 review in the British Journal of Sports Medicine found that exercising for an hour (or more) can lead to decreases in leptin, the appetite-inhibiting hormone. This may sound like a negative thing, but it’s not. Here’s why: the release of leptin from your fat cells sends a message that you don’t need more food. But people with high levels of leptin (due to obesity) can suffer from leptin resistance; their brains are overwhelmed by the signals, so no message to put down the fork is sent out. However, exercise appears to help fine-tune your leptin sensitivity.

Working out may also help you improve your food choices. According to research by Dr Miguel Alonso-Alonso, a neurologist at Beth Israel Deaconess Medical Center, exercise helps you stick to a plan by enhancing your brain’s executive function. “This means you’re better at both inhibiting the temptation to overeat and resisting the impulse to eat junk.” He notes that these benefits accrue over time, so it’s critical to keep exercising even after you hit your target weight. WINNING STRATEGY: Joe Dowdell, founder of Peak Performance in New York City, advises doing a mix of strength training and intervals for a total of 3½ to 4½ hours a week.

The rise in obesity is mirrored by an epidemic in sleep deprivation: nearly one in three Americans log less than six hours of pillow time a day. A study in the Journal of the Academy of Nutrition and Dietetics recently confirmed that sufficient sleep is critical for weight loss. Tired people tend to overeat, says Dr Christopher Winter, medical director of the Martha Jefferson Hospital Sleep Medicine Center. “Your brain likes being awake. It will take great measures to promote activity, even if it has to eat itself awake.” These great measures include decreases in leptin and increases in appetite-boosting ghrelin, a weight loss gremlin because it tends to push you towards simple carbs, fats and sugars, says Winter. WINNING STRATEGY: In the short term, sip coffee or green tea, says Winter. They’re low in kilojoules and the caffeine helps tamp down tiredness. Of course, the real solution is enjoying at least seven hours of shut-eye nightly. The key is to figure out your wake-up time and stick to a routine. Count the hours back to determine when you should already be asleep. So if your alarm squawks at 7am, then you should be relaxed, with the lights out and your head on the pillow by 11.45pm.